Apparatus for recording perpendicular magnetic fields in transverse tracks on a magnetic tape



3 1968 R L. HOLLINGSWORTH 3,419,683

APPARATUS FOR RECORDING PERPENDICULAR MAGNETIC FIELDS IN TRANSVERSETRACKS ON A MAGNETIC TAPE Filed Dec. 4, 1964 Sheet of 2 IN V EN TOR.

3 1968 R HOLLINGSWORTH 3,419,688

APPARATUS FOR RECORDING PERPENDICULAR MAGNETIC FIELDS IN TRANSVERSETRACKS ON A MAGNETIC TAPE Filed Dec. 4. 1964 Sheet .2 of 2 INVENTOR.F155 az4/A/swaer// 4770E VE) United States Patent ABSTRACT OF THEDISCLOSURE An apparatus for magnetically recording transverse the lengthof a tape. A rotating magnetic distributor with a plurality of arms isarranged axially of a pair of opposed semi-circular magnetic members. Atape is driven between the rotating distributor arms and one of thesemi-circular members in such a manner that perpendicular magneticfields are recorded in transverse tracks on the tape.

The present invention relates to magnetic sound, video and computertranslators and recording systems and is a continuation-in-part of mypending application Ser. No. 36,678 filed June 16, 1960 now Patent No.3,236,942. In the case of multi-track magnetic tape recording, it isnecessary to have means for recording on, or reading off of, eachintelligence bearing magnetic track areas individually, at high speedscanning rates, or at high speed transverse continuous area scanningduring record and readout.

The present invention provides transducer head and magnetic distributormeans having a magnetic material of highly permeable alloys or ironoxide, or magnetic material plating to better conduct high speedmagnetic impulses to a concentrated magnetic translation point or area.

In the present invention, there is provided means to accomplish highspeed transverse scanning of magnetic tape, said tape being accuratelyguided along a concentrated three part curvature conforming portion of arecording head means.

In accordance with the present invention, the recording of electricalsignals comprising television signals and sound signals, and signalscorresponding thereto at least in part, and recording and storingsignals corresponding to various kinds of physical observations,including radar and transponder signals and business machine data, isaccomplished.

The present invention provides means comprising at least a two-piecemagnetic circuit recording head device in which the winding carryingpiece is selectively magnetically energizable to the magnetic tape,wherein the tape may or may not be physically touched by the parts ofthe magnetic head means. This saves wear on the tape and on the highspeed distributor means.

The present invention also provides a multiple channel recording head bythe simple means of positioning a rotatable magnetic distributor at apredetermined po* sition relative to a curved magnetic tape width torecord on, or readout from the tape, intelligence from one, or from anyone or more tracks simultaneously, or from one of one hundred or morelongitudinal record read 5 tracks, avoiding the use of multiple magneticgaps and their necessary electric windings to each head, and the use ofcomplicated multiple selector switches. The elimination of all of theseelectrical circuits, and electric switching means normally used inmulti-track recorders, makes the present invention highly desirable, andan example of the dexterity of an information storage and retrieval P cesystem for computers and generally recorded intelligence is as follows:Assume a magnetic tape four inches wide is passed through at least aportion of a circular magnetic gap area, whereby a sharp pointedmagnetic distributor makes magnetic contact with the magnetic tape toestablish a magnetic loop circuit, either in high speed synchronousscansion rotation to provide transverse recording and readout, or wherethe magnetic distributor is stopped at a calibrated holding point totranslate along any one of perhaps five hundred separate lines runninglengthwise of the tape. Here the positioning of the distributor may beby an automatic selector means such as a dial phone mechanism, counterstepping mechanism, resistor and shaft positioning means, automaticharmonic impulse stepping means as used in channel selecting of oneradio channel out of one thousand, or any other suitable precision shaftpositioning means. By the time the shaft is positioned, the tape whichdoes not have to be too long normally due to having four to five hundredchannels, is by this time reeled up to the point of the storedinformation or to the point where information is to be stored. Thereforea rather simplified form of magnetic tape computer or reference libraryof information is provided, which, when connected to a printout orwriteout means, provides the information almost immediately in final andusable form. If a longer tape be used, additional retrieval time may berequired to reach a portion of the information. However, billions ofbits of information can be stored and retrieved from one roll of suchtape. If the distributor has at least two or more sharp pointed magneticarms or magnetic gaps positioned so that when one is leaving the tape,another is starting to traverse the tape at the opposite side orposition on the tape, whereby a radio frequency carrier may be recordedthat has modulated thereon a great multiplicity of sideband informationchannels, each carrying a very large volume of information, then thetape need only be positioned longitudinally, and to the channel desiredto be translated, that is, recording or readout is accomplished by beingconnected directly to a printout means through a separate detector andfiltered amplifier channel. Such is not however, as simplifiedcircuit-wise as the positioning of the rotating or positionabledistributor means.

The rotating distributor means according to the present invention, maycomprise a rotating magnetic gap means to make brushing contacttransversely of the moving tape, guided by the previously mentioned tapeguilding means, said multiple gap means being commonly fed with energyto be recorded and supplied through a set of slip ring contacts attachedto the rotating shaft from stationary brushes. This statement, exceptfor the combination of the rotating gap and the guiding and holdingmeans, in itself is known in the art. But when the recording gaps :areadjusted so that the gap lengththe distance between the poles of thegap-defines the width of the transverse line to be recorded--here then,is something new. That is, it is new to record the information inextremely narrow parallel transverse lines across the tape according tothe length of the gap. A portion of each impulse along each line may bere-recorded, or recorded over. This system also confines the recordingactivity in lines the width of which is equal to the length of the gapwithout line overlap, thus making it possible to position the recordedtransverse lines so close together, that each may contain a horizontaltelevision picture line in a manner to provide a magnetic picture thatcan be transversely scanned without regard for line travelsynchronization and tape skewing. If the magnetic distributor heretoforementioned is brought to a very 0 sharp point as it conducts the magneticpulses to the tape, the magnetic packing density approaches that ofphotography. A gap may be positioned to record in longitudinal lineswith the recording gap positioned for rerecording a portion of eachsupplied impulse. For readout, the gap would be rotated on its shaftmount or 90 the tape passed through a separate readout gap, howeverdesirable echo effects may be obtained by using the same gap for readoutthat was used for recording.

In one embodiment of the invention a horseshoe magnet has arecord-readout winding mounted thereon, and the ends of the poles areextended and shaped to form substantially a half, but divided circleareas, wherein provisions are made to pass a magnetic tape. An insertedgroove in the tape guard and guide is provided to carry the leading edgeof the tape to protect the edge from the magnetic distributor means thatis mounted on a shaft in the center of the magnetic circle areas of thetwo magnetic poles when the tape is physically brushed. A resilient feltor rubber area is preferably provided within the curvatures of themagnetic tape guide and guard circle area, when the recording andreadout action utilizes a magnetic translating head unit having amagnetic gap that brushes the tape in its transverse scanning actionacross the tape. To assist in keeping the tape or tapes in the recordingcurvature area and not within an edge protecting slot, there ispreferably a first and third gap assembly section of nonmagnetic guidingcurvature area located close to either side of the magnetic curvatureareas and their supporting means, so that the tape is guided positivelybefore and after passing through the magnetic curvature area, unlikeother systems that use an air suction means to hold the tape in a curvedarea while it is scanned or brushed by rotating magnetic head gaps, orby magnetic distributors as herein described. The supporting means forboth the head gaps and the sharp distributor points may extend to theends of the gap or to the ends of the sharp points or sharp edges of thedistributor so that, mechanically speaking, the tape is brushed with asmooth wheel that is nonmagnetic except for the recording head gaps orthe magnetic distributor points or edges. It is to be understood thatthe intensity of the magnetic energy may be increased to providemagnetic etching according to my pending patent application Ser. No.145,805 filed Oct. 18, 1961, or that electricity be applied to thedistributor and to the curvature areas to produce recording or printingon a tape having a surface sensitive to an electric arc or to the flowof electricity through or along the surface of the tape. The magneticdistributor may comprise a multiplicity of arms and the magneticcurvature areas may be somewhat increased in circumference so that whenone television horizontal line is recorded on one transverse recordedline across the tape, the rotating speed of the distributor is notincreased over speeds used in the prior art, and this speed may even bedecreased. To fully distinguish from the prior art one must take intoconsideration the total head, distributing means and the total overallresult.

The prime purpose of the present invention is to provide a new and novelmagnetic recording system.

Another purpose of the invention is to provide a new and novel tapeguiding means for tape as used in magnetic recording machines, computersand in facsimile transmission and reception and for making printing andduplicating stencils, printing plates by magnetic etching by magneticremoval recording according to the aforesaid pending patent application,or by punching holes in the tape by the same magnetic removal techniquewhen the tape has a great plurality of holes therethrough and which arefilled with a magnetic composition that can be selectively removedaccording to modulations or by prepared and timed impulses, orselectively punched out by applied magnetic impulses.

The invention will now be briefly explained with reference to theaccompanying drawings. The elements of the drawings are identified bythe same numerals as Were used in the pending patent application ofwhich this is a continuation in part application.

FIGURE 1 shows a guideway for the passage of at least one magnetic tapeheld in a curvature during its passage via a stationary magneticrecording area.

FIGURE 2 is a side view of the stationary horseshoe magnetic area thatforms the center portion of FIGURE 1. This figure shows an end view of arotatable shaft on which are mounted the magnetic distributor arms thatselectively connect magnetic energy through the tape to selectivelymagnetize the tape.

FIGURE 3 shows an embodiment of FIGURE 2 which can accommodate up to onehundred and five distributor arms which by five shaft revolutionsprovides recording for one fully scanned 525 line picture frame, eachhorizontal picture frame line being recorded across preferably aone-quarter inch tape. At thirty frames per second, a speed of 9000 rpm.is required to record each transverse line across the tape, making aseries of magnetic pictures on the tape that can be magnetically scannedfor readout or for re-transmission as in television tape transmission,and in transferring magnetic energy to an electrostatic cathode rayprintout, developer and dryer. These magnetic pictures may be passedthrough colored magnetic powder in suspension, dry or liquid, and aftercollecting magnetic powder within a given time period as a controlledapplication of the powder, the tape or sheet is treated with a fixer andutilized.

FIGURE 4 is a side view of FIGURE 3.

FIGURE 5 shows an embodiment of the invention wherein the magneticrecording gap is positioned to scan the tape, with the gap movingsideways across the tape to confine the width of the transverse lines tothe length of the recording gap. This figure is also representative of adistributor means having a length such that it may provide arecording-over effect between the impulses to be recorded one after theother along each transverse line.

I Will now describe my invention in detail.

FIGURE 1 illustrates apparatus and structural means for guiding arecording tape of any type, and particularly a magnetic recording tapethrough a curved surface area where the tape is scanned by a recordinggap attached to a shaft, or by a magnetic distributor according to thepresent invention. The edge of the tape is protected from being torn bythe scanning mechanisms as illustrated by FIGURES l, 2 and 3. Recordingtapes 1 and/or 1a are shown curved and fitted in the upper and lowerportions of magnetic gap areas 183 and 184, which are magneticallyscanned by eccentric gap distributor means 182 and 182a, or the tape isbrushed by a recording gap of a rotating head of the prior art, not hereillustrated, or by a recording head according to FIGURE 5 hereof. Thetapes 1 and 1a are threaded over circular guide 197, through themagnetic curvature areas 183 and 184 and continues over circular guide198. Guides 197 and 198 are precision made and are mounted to exactlyguide tapes 1 and 1a precisely along the magnetic circle areas 183 and184. Circular guides 197 and 198 may be slidably adjusted along thedirection of the shaft or supporting means not shown, to facilitate tapethreading. They may also be divided and hinged to facilitate placing thetape in the magnetic curvature area for record or readout. The movementof tapes 1 and 1a are from a tape reeling means, through the guide meanspast the scanning magnetic distributor means or of a scanning magneticgap means; via a capstan and onto a tape takeup reeling means. In oneside of the magnetic pole face areas 183 and 184 of the tape guidingmeans, is shown a tape edge protecting groove 199. This protection forthe tape edge may only be provided in the guiding means either side ofthe magnetic recording curvature areas 183 and 184. This allows the tapeto be held very closely and firmly in the curvature by guideways closelypositioned either side of the curved magnetic pole areas 183 and 184. Ifthe magnetic areas 183 and 184 contain the groove to protect the edge ofthe tape, the ends of the distributor means 182 and 182a do nottranslate across the entire width of the tape, however if the guidewayor guiding means 183 and 184 are located very closely to the magneticcurved areas on either side of the magnetic curvature area, then thedistributor or any rotating recording gap means may safely brush thetape across its full width without inflicting mechanical injury to theleading edge of "the tape. In operation, signal energy to be recorded isconnected to terminals 189 and flows through coil 190, which is woundupon the magnetic material loop that is extended to form magnetic areas183 and 184. As magnetic distributor arms 182 and 182a rotate with theshaft located in the center of the magnetic circle formed in magneticareas 183 and 184, recording, or readout is accomplished on or from tape1 and 1a. During readout the magnetic impulses from the tape areselectively sensed and their magnetic lines of force are transferredfrom the tape to flow within the magnetic loop formed by the horseshoemagnets 183 and 184 and the rotating distributor arms 182 and 18211, toinduce electric energy into coil 190 and appears across terminals 189,which is normally connected to a video amplifier and reproducer system.During reproduction, only one of the tapes is run through the machine asit would be rather difficult and possibly impractical to pull both tapesat exactly the same speed as during recording, since from ten to twentyhorizontal lines of a television picture signal is recorded on one orboth tapes each time an arm 182 passes transversely over one or both ofthe tapes. In another mode of operation, as 182 is passing off of tape1, counterclockwise as an example, an arm 1820 has already started aseparate transverse line. The exaggerated angle of displacement ofdistributor arms 182 and 182a is of no consequence in this instance, andthey may be mounted exactly opposite or 180 apart. When one sweep of anarm 182 across the tape represents one horizontal line of a televisionpicture, then arms 182 and 182a may be olfset the exact amount toproduce a form of halftone pattern by slightly displacing eachsucceeding line lenthwise across the tape a small amount from eachother. When the outer ends of distributor arms 182 and 182a are broughtto a sharp point, the magnetic impulses flowing into magnetic areas 183and 184 are concentrated directly to the tapes in extremely narrow lineswhich can be as close together as a fraction of a mil, however there isa practical limit to both the narrowness of each transverse line andtheir adjacent separation space, plus the ability of the distributor toretract each transverse line during readout, At present, five mil widthof each transverse line with five mil separation is a fair compromise asto line width and line separation, however precision mechanicalimprovements promise to reduce both the line width and spacing.

The angle of travel of the transverse recording lines is indicated asbeing almost at right angles to the tape length, however the circularareas 183 and 184 may be made to receive the tape at an angle such that,on a one inch wide tape, each transverse line may be somewhat longerthan one inch, however the lines are straight so that the packingdensity does not change as the lines are recorded.

In FIGURES 3 and 4, the invention provides for up to one hundred fivemagnetic distributor arms, which by five shaft revolutions provides onefully scanned 525-line framed picture, each horizontal picture linebeing re corded across preferably a one-quarter inch wide tape. Atthirty frames per second, a speed of 9000 rpm. for the distributor shaftis required to record each transverse line across the tape, making aseries of magnetic pictures on the tape that can be magnetically scannedfor readout or for transmitting over a television station again andagain. These magnetic pictures may be subjected to dispersed magneticpowder in air, even under compression, or in a liquid solution, toproduce viewable pictures by the settling of the powder on the magnetictape having the magnetic picture recorded thereon. If the recordingtakes the form of magnetic removal, that is, lifting elemental parts ofthe iron oxide from the tape according to picture modulations, then thepictures are viewable direct and by projection enlargement, and becomesan excellent substitute for micro-film instantly without chemical orheat treatment of any kind.

In FIGURE 3 the energy to be recorded is also supplied to terminals 189and flows through coil to produce opposite magnetic polarities betweenflat magnetic areas 183 and 184. The separation distances 187 and 188between 183 and 184 are sufficient that no magnetic losses occur between183 and 184. Distributor arms here represented by 182 and 182a comprisea total of up to one hundred five arms attached to and extended frommagnetic hub member 185, which is attached to preferably non-magneticshaft 186. Guiding member 191 and 192 are positioned each side ofmagnetic areas 183 and 184 as illustrated in FIGURE 4, and by the dottedline areas 191 and 192 in FIGURE 3. Here tape 1, and 101 if usedsimultaneously, are moved through guide means 191 and 192. During thepassage they are held in position by extension guides 191a and 192a,which are positioned adjacent to 183 and 184 at the circle areas atraised areas 183a and 184a to guide the tapes directly over these raisedareas, so that the ends of magnetic distributors 182 and 182a are activeonly when passing over the tapes to complete the magnetic loop throughthe tapes, and as each of the up to one hundred five distributor armpass over the tape. It is to be noted that recording continuity isprovided by an overlap between the succeeding distributor arms, that is,as one has traversed the tape width and as it is about to leave thetape, the next succeeding distributor point is starting its excursionacross the tape to provide recording continuity, In this manner then,continuity is maintained between the adjacent lines. However, thiscontinuity between the transverse lines as here described, is notrequired if each transverse line records one horizontal televisionpicture line. With continued improvement in video tape as to magneticoxide grain sizes and uniform distribution on the tape, it appears thatit may soon be possible to record as much as from five to ten horizontaltelevision picture lines within one transverse line across a one-quarterinch wide tape.

FIGURE 4 shows an edge view of FIGURE 3 looking into the separationdistance 188 between the ends of magnetic areas 183 and 184. Tape 1 isshown curved in the set-a-part portion of the drawing, as it passesthrough guide means 191 and 192, and extended guide lips or extensions191a and 192a. Here distributors 182 and 182a are held rigid by a formedmeans 18217 shown in cut-a-way, 183 and 184 being preferably very thinto accommodate the travel of rapidly changing and occurring magneticenergy. Also shown supported by a non-mag netic means 18% which maycomprise bonded ceramic or aluminum plates fitted to the sides of 183and 184 to lend it supporting strength and provide magnetic insulationfor magnetic areas 183 and 184. This means of support may take variousforms. The thickness of magnetic areas 183 and 184 may be very thin,even a few microns in thickness and the distributor contact width may besharp edged and considerably broadereven one milto overcome transverseline tracking eccentricities during record, and during readoutparticularly. Magnetic areas 184a are raised above the circular area,and adjustable if desired, to make very close magnetic contact with thesharp points or sharp edged shapes of magnetic distributors 182 and18212, not leaving room for the passage of tape 1a, to increase theefficiency of magnetic transfer through tape 1 from magnetic area 183and 184 according to the electrical wave energy applied to inputcontacts 189. In FIGURE 3, it is to be appreciated that more than onetape may be recorded simultaneously by providing more pairs of magneticraised sections 184a and tape passage guiding means 191 and 192 for anyadditional raised sections. If only one or two tapes are desired to berecorded at the same time, the circular magnetic areas 183 and 184 needonly extend to accommodate two raised magnetic members 184a opposite ofeach other. It is to be further appreciated, that two or more tapes mayalso be placed in the same slot and the magnetic energy passed directlythrough the several thicknesses of tape to provide exact multiplerecordings. These sharp pointed magnetic arms may indeed be scallopedout of a circular magnetic disc which would be capable of supportingitself Without supporting means 1821) being attached or applied thereto,the disk being magnetically insulated from the shaft 186.

FIGURE illustrates another embodiment of the invention wherein a tape 1is supplied from a reeling or transport means indicated by the woundtapes, of sufficient accuracy in tape transport, and the tape is held ina curvature preferably according to FIGURES 1 and 3, including thedesired tape guiding means. A rotatable shaft 186 is positioned at thecenter of the curvature of the tape. Slip rings 186a are placed on shaft186 and are electrically insulated from the shaft by insulating bushings186a. Coil 190 that is wound on recording head 1820 receives electricenergy that is applied to video input terminals 189, via brushes 18GbWhih are in electrical brushing contact with slip ring contacts 186a.Magnetic recording head 182s is attached to shaft 186 in a suitableremovable and adjustable manner, of which there are numerous ways ofattachment of this head to the shaft. The recording head gap 182d is sopositioned by the size of the recording head that it makes accuratepressure contact (preferably) on the magnetic surface of the recordingtape 1. Also where the brushing gap is utilized with the curvatureguiding means according to the present invention, the circular area maybe lined with resilient material to allow fluid-like pressure effectsbetween the recording gap and the tape. It is to be noted that therecording gap moves sideways across the tape, and the width of eachtransverse line is defined by and confined in width to the length of themagnetic gap 182d. The magnetic material of the recording head 1826 maybe relatively thin and mechanically weak, therefore the head may besuitably supported by an applied ceramic, or other, supporting means182b, In practice there would be a plurality of these recording headspositioned around shaft 186 so that as one is completing a transverserecording line, another head has instantly begun recording the nexttransverse line, thus continuity of recording is provided. The wear ofthe head gap and of the distributor points of FIGURES 2 and 3 due tocontact with the tape is minimized and governed by the wear of theceramics. Let us assume that recording gap 182d is one sixteenth inchwide and that the length of the gap is one mil in length, or thedistance between the poles of the magnet. As the head rotates it willrecord transversely in lines across the tape one mil broad upon thetape. This gap can be very short in length, even infinitely short if.excited in opposite phase relation to produce opposed poles to cause themagnetic wave energy to be strongly projected through the tape, as setforth in my patent application 841,822, filed Sept. 23, 1959, nowbearing Ser. No. 179,281. In high speed impulse rate recording, a firstpulse or character is recorded. Before the gap moves off 01 thisrecorded signal element, the next impulse is at least in part recordedover a portion of the previously recorded impulse. Here the efificiencyof recording is somewhat increased as each re-recorded bit of space istranslated at the instant, as if the entire tape had been premagnetized.This degree of increased efiiciency varies of course with the strengthof each previously recorded impulse and the length of both impulses.This re-recording, or recording over technique, came about in searchingfor a way to more accurately define the widths of closely spacedtransversely recorded lines, and the recording efficiency was found tobe inherent with this sideways movement of the recording gap orrecording head. The gap width, not the gap length, may be reduced to aslittle as .00001 inch. The line width would still be accurately definedand the re-recording eifect would not be present to any degree with thissideways movement of the recording head. This gives a longer wavelengthto the gap, and adds emphasis to the recording of the lower videofrequencies. Such a gap may be as long as five mils as it would record aline five mils wide. This type of recording head may be used inlongitudinal recording for either single or multiple track recording andin reproduction. Head 182c of FIGURE 5 may be rotated degrees on itsshaft mount, back to a conventional position for recording or forplayback. A calibrated dial and holding means not shown may be placed onthe end of shaft 186 and be used for selecting longitudinal linepositions on the tape, and such selection may be accomplished accordingto one of many types of automatic dial or shaft positioning devices, orby hand. A recording machine having a relatively broad tape with meansfor automatically positioning the tape to a desired point of translationon the tape, and means to position recording head 1820 of FIGURE 5 to agiven longitudinal line position along the tape, such machine provides amassive information magnetic storage and readout means.

In carrying the invention into practice in various ways to servedifferent commercial, educational, and entertainment uses, all knownmeans of electronic amplification, modulating and de-modulating systems,limiting, signal expander means, signal multiplication devices, electricdelay lines and delated action amplfiers for superimposing one pictureframe over the other to double the picture lines, and all signaltreatments known to the electronic and communications art and sciencesare contemplated when desired or required in carrying the invention intopractice, when used in combination with the invention as basicallydescribed and set forth herein.

It is to be appreciated, that when the transverse lines for a series ofmagnetic pictures corresponding to each television picture frame arerecorded, the information may then be readout by passing the tape overthe cathode ray magnetic sensing means which provides a large number ofmagnetic sensing wires sealed in a fine line across the face orflattened end of a cathode ray tube whereby the magnetic impules on thetape are physically connected into the tube to produce variations of thehigh speed scanning cathode ray beam, and these variations are sensedand connected to a visual reproducing means, thus providing high speedall electronic readout of the pictures or magnetic information stored onthe tape. It is to be also appreciated that when energy is picked upfrom a magnetic recording, especially by a cathode ray tube magneticscanning means, this energy may be controlled by the same scanningenergy and used to apply enlarged electrostatic charges to anelectrostatic paper via an electrostatic cathode ray tube recording andelectrostatic image reproducing means, thus providing a combination toprintout from a magnetic tape with no mechanical motion except the tapemovement, in continuous fashion, or by frame sequence movement as in amotion picture film when being exposed and projected.

It is to be especially appreciated that when the transverse scanningprovides a magnetic picture by magnetic recording on magnetic tape, andwhen the use is for filing of records, the visual reproduction byassociation with magnetic powder to render the picture viewable, needonly be accomplished if and when the record is required, since proof ofrecording would be viewed or observed instantly after recording on atelevision monitor.

Other and further embodiments and use of the instant invention will beappreciated by those skilled in art by virtue of both this specificationand the appended claims. The foregoing embodiments are illustrative andnot limitative of my invention.

What is claimed is:

l. A magnetic tape recording system comprising flat semi-circularmagnetic areas arranged to form a loop with diametrically opposite gapssized to prevent magnetic losses, the magnetic areas at one gapextending beyond the loop to form a support connecting the magneticareas, a coil encircling a portion of said support to provide energy tobe recorded from terminals serving, as input contacts to whichelectrical energy is supplied, thereby pro-' ducing opposite magneticpolarities between said magnetic areas, a non-magnetic shaft mounted forrotation axially of said loop, a magnetic hub member on said shaft, aplurality of magnetic distributor arms extending radially from saidshaft in angularly equi-spaced relationship and scanning saidsemi-circular magnetic areas during rotation, at least one tape movablebetween one of said semi-circular areas and said distributor arms andguided by guiding means disposed within and close to the inner edgesurface of the semi-circular magnetic area, the tape being guided over araised magnetic area of said semi-circular magnetic area so that theends of the distributor arms are active only when passing over saidtape,

2. A system according to claim 1 in which there are two tapes and anequal number of raised magnetic areas in diametrically oppositepositions.

3. A system according to claim 1 in which the semicircular magneticareas are provided with non-magnetic protection.

4. A system according to claim 1 in which the arrangement is such thatrecording continuity is provided by overlap between successivedistributor arms whereby as one such arm traverses the tape width and asit is about to leave the tape the next succeeding distributor arm startsacross the tape, to maintain continuity between adjacent lines.

5. A system according to claim 1 in which the distributor arms areformed into a supporting non-magnetic wheel.

6. A magnetic tape recording system comprising fiat semi-circularmagnetic areas arranged to face each other and form a magnetic loop anddiametrically opposite gap areas, an exciting coil encircling a portionof said loop, to provide energy to be recorded from terminals serving asinput contacts to which electrical energy is supplied,

thereby producing opposing magnetic polarities between said magneticareas, a non-magnetic shaft mounted for rotation axially of said gapareas, a magnetic hub member on said shaft, a plurality of magneticdistributor arms extending radially from said shaft in angularly spacedrelationship and scanning said semi-circular magnetic areas duringrotation, at least one tape movable between one of the magnetic circulararea, semi-circular areas and said distributor arms and guided byguiding means disposed adjacent to the semi-circular magnetic areas, thetape being guided over a raised magnetic area of said semi-circularmagnetic areas so that the ends of the distributor arms are active onlywhen passing over said tape.

7. A magnetic tape recording system comprising flat semi-circularmagnetic areas arranged to face each other and extended to form amagnetic loop and diametrically opposite surface gap areas, an excitingcoil encircling a portion of said loop to provide energy to be recordedfrom terminals serving as input contacts to which electrical energy issupplied, thereby producing opposing magnetic polarities between saidmagnetic areas, a non-magnetic shaft mounted for rotation axially ofsaid gap surface area, a magnetic hub member on said shaft, a pluralityof magnetic distributor arms extending radially from said shaft inangularly spaced relationship and scanning said semi-circular magneticareas during rotation, at least one tape movable between one of thesemi-circular magnetic areas and said distributor arms, and guided byguiding means disposed adjacent to the semi-circular magnetic areas.

References Cited UNITED STATES PATENTS 2,743,318 4/1956 De Forest179-l00.2 2,965,708 12/1960 Witt 179-100.2 2,575,742 11/1951 Baltin eta1 346-74 3,099,709 7/1963 Barry 179-l00.2

BERNARD KONICK, Primary Examiner. J. R. GOUDEAU, Assistant Examiner.

US. Cl. X.R. 178-6.6; 346-74

